Changes are $3 per ticket, plus any increase in ticket price. Changes can be made accessing your "My Account" starting September 12th.
"My Account" can be located two ways
On your Order Confirmation all the way at the bottom you will see a button labeled My Account, this button will give you direct access to your My Account
Visit this link to Manage Your Order
Enter the email address used to purchase your tickets
An email will be sent to that email address with a direct link to your My Account